1. Field of The Invention
This invention relates to new and improved apparatus and method for signal generation and for signal processing which are particularly adapted for use attendant optical/electronic sample analysis.
2. Description of The Prior Art
Although a wide variety of apparatus and methods for signal generation and signal processing are, of course, known in the prior art, none are known to be configured and operable in the manner of those of this invention, particularly as applied to optical/electronic sample analysis.
More specifically, and regarding signal generation, although the combined fixed sample beam mirror and rotating optical chopper assembly disclosed by Technicon Instruments Corporation of Tarrytown, N.Y., at the Pittsburgh Conference of Analytical Instrumentation in March, 1981, does function to generate sample and reference beams for direction into an integrating sphere attendant spectroscopic quantitative sample analysis, that assembly does not include alternating sample, reference and dark segments; whereby the electronic signals generated attendant the detection of those sample and reference beams per se do not constitute a single composite or multiplexed analog data signal containing, in precisely timed sequence, all sample, reference and dark data required for calculation of the sample analysis results.
Regarding signal processing, it may be understood that the Technicon Instruments Corporation disclosure here under discussion contemplated the use of a conventional analog phase lock loop driven directly off of the analog data signal to produce the requisite reference or control signal. This technique is disclosed in detail, for example, in Electronics and Instrumentation For Scientists by H. V. Malmstadt, et al., as published in 1981 by The Benjamin Cummings Publishing Company, Inc. of Menlo Park, Calif. and is known to give rise to problems of reference vis-a-vis data signal time lag, and variation in reference signal level in accordance with variation in data signal level. Alternatively, although the use of commonly driven encoder devices to generate the requisite reference or control signals attendant the operation of rotatable optical beam generation devices or the like is also well known in the prior art, in many instances simple mechanical alignment between the encoder and beam generation devices is relied upon for the requisite data-control signal alignment in time. This mechanical alignment technique is simply not sufficiently precise for the purposes under discussion. Too, although non-mechanical apparatus and methods of optical beam generated-encoder generated signals alignment have been proposed, none are known to be configured or operable as disclosed herein, or to provide the particularly high degrees of signal alignment precision and stability as are provided by the apparatus and method of this invention.